Method for detecting a wind turbine blade

Abstract

The application relates to the field of wind power generation technology and discloses a wind turbine impeller detection method. The wind turbine impeller detection method comprises the following steps: a main shaft locking disc is sleeved on a main shaft of a wind turbine, the main shaft locking disc can rotate with the main shaft, a plurality of trigger structures are arranged on the main shaft locking disc at intervals in the circumferential direction; a proximity switch is fixedly arranged on a machine base, a main shaft torque test module is arranged on the main shaft and is used for outputting a voltage signal according to forward rotation and reverse rotation of the main shaft, the proximity switch and the main shaft torque test module are both signal-connected with a control module; after starting, the main shaft rotates, when the proximity switch is triggered by a trigger structure for the first time, the proximity switch outputs a first detection signal, and the control module starts to arithmetically accumulate the number of detection signals; the control module calculates an impeller angle corresponding to a triggering moment of the proximity switch by means of an arithmetical accumulation value of the detection signals and a voltage signal output by the main shaft torque test module. The method avoids the influence of impeller swing on the calculation result.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, and more particularly to a method for testing the rotor of a wind turbine. Background Technology

[0002] The SCADA (Supervision and Data Acquisition) system of wind turbines typically only measures and records the rotor speed and generator speed, without measuring and recording the rotor angle. Traditional methods using inductive encoders to measure the rotor angle have several drawbacks: the need to customize encoders to the appropriate size based on the drivetrain dimensions, the existence of corresponding installation space and location on the drivetrain, and the need to fabricate a plan for encoder fixing and subsequent disassembly. Traditional methods also suffer from increased testing costs, significantly longer test preparation cycles, and poor versatility of customized encoders. Furthermore, when the wind turbine is in a stopped, rotor-retracted state, the back-and-forth oscillation of the rotor means that calculating the phase angle solely by counting proximity switch triggers will result in significant errors.

[0003] Therefore, there is an urgent need for a method to test the rotor of a wind turbine to solve the above problems. Summary of the Invention

[0004] Based on the above, the purpose of this invention is to provide a method for detecting the impeller of a wind turbine, which can calculate the impeller angle more accurately and avoid the influence of impeller oscillation on the calculation results.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] Methods for testing the rotor of a wind turbine include:

[0007] A main shaft locking disc is fitted on the main shaft of the wind turbine. The main shaft locking disc can rotate with the main shaft. Multiple triggering structures are arranged at intervals along the circumference of the main shaft locking disc.

[0008] A proximity switch is fixedly installed on the machine base, and a spindle torque testing module is installed on the spindle to output voltage signals according to the forward and reverse rotation of the spindle. Both the proximity switch and the spindle torque testing module are connected to the control module.

[0009] After power-on, the impeller and the main shaft rotate. When the proximity switch is first triggered by one of the triggering structures, the proximity switch outputs the first detection signal, and the control module begins to arithmetically accumulate the number of detection signals.

[0010] The control module calculates the impeller angle corresponding to the triggering moment of the proximity switch by using the arithmetic sum of the detection signal and the voltage signal output by the spindle torque testing module.

[0011] As a preferred embodiment of the impeller detection method for wind turbines, when the impeller rotates forward, the voltage signal output by the main shaft torque testing module is a positive voltage signal, and when the impeller rotates in reverse, the voltage signal output by the main shaft torque testing module is a negative voltage signal. When the control module performs arithmetic accumulation on the detection signals, it adds one based on the positive voltage signal or subtracts one based on the negative voltage signal.

[0012] As a preferred embodiment of the wind turbine rotor detection method, the number of triggering structures is n, and the control module performs arithmetic accumulation of the detection signals, including the following steps:

[0013] When the arithmetic sum of the detection signal is n, the control module clears the arithmetic sum of the detection signal to zero and re-accumulates the number of times the detection signal is detected.

[0014] When the arithmetic sum of the detection signal is -1, the control module corrects the arithmetic sum of the detection signal to n-1, and then performs arithmetic summation again based on this.

[0015] As a preferred embodiment of the wind turbine rotor detection method, the interval between each two adjacent triggering structures is equal, and the included angle between each two adjacent triggering structures is θ.

[0016] When the control module receives the positive voltage signal and the arithmetic sum of the detection signal is a, the impeller angle α corresponding to the triggering time of the proximity switch is aθ.

[0017] When the control module receives the negative voltage signal and the arithmetic sum of the detection signal is a, the impeller angle α corresponding to the triggering time of the proximity switch is α = aθ + θ.

[0018] As a preferred embodiment of the wind turbine rotor detection method, after the control module calculates the rotor angle corresponding to the proximity switch triggering time, the method further includes the following steps:

[0019] The control module calculates the average impeller angular velocity based on the difference in impeller angles corresponding to two consecutive proximity switch triggers and the corresponding time interval.

[0020] As a preferred embodiment of the impeller detection method for wind turbines, after the control module calculates the average impeller angular velocity, the control module can calculate the impeller rotational speed based on the average impeller angular velocity.

[0021] As a preferred embodiment of the wind turbine rotor detection method, after the control module calculates the average rotor angular velocity, the method further includes the following steps:

[0022] The control module calculates the impeller angle at any given time based on the average impeller angular velocity and the impeller angle corresponding to the proximity switch triggering.

[0023] As a preferred embodiment of the method for detecting the impeller of a wind turbine, a moment patch is further included. The moment patch is disposed on the main shaft and used to measure the absolute moment value of the main shaft. The moment patch is connected to the control module for signal transmission. After the control module calculates the impeller angle at any given time, the method further includes the following steps:

[0024] The control module calculates the equivalent bending moment values ​​of the fan in the horizontal and vertical directions based on the absolute bending moment value and the impeller angle at the corresponding moment.

[0025] As a preferred embodiment of the method for detecting the rotor of a wind turbine, the control module includes a data acquisition unit and an industrial control computer. The proximity switch is signal-connected to the data acquisition unit, and the data acquisition unit is signal-connected to the industrial control computer. When the triggering structure triggers the proximity switch, the proximity switch outputs a pulse signal. The data acquisition unit receives the pulse signal, and the industrial control computer performs an arithmetic summation on the number of pulse signals received by the data acquisition unit.

[0026] As a preferred embodiment of the rotor detection method for wind turbines, the triggering structure is a bolt, and multiple bolts are spaced apart along a first circumference on the main shaft locking disc. The proximity switch is directly opposite the position of the first circumference. When one of the bolts is directly opposite the proximity switch, the proximity switch outputs a detection signal.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention provides a method for detecting the impeller of a wind turbine. The method includes a main shaft locking disc, a proximity switch, a main shaft torque testing module, and a control module. When the impeller rotates, the main shaft locking disc on the main shaft rotates accordingly, causing a triggering structure to rotate relative to the proximity switch. Each time a triggering structure passes the proximity switch, it triggers the proximity switch to output a detection signal. The control module arithmetically accumulates the number of detection signals. Furthermore, the control module can determine whether the impeller is rotating forward or backward based on the voltage signal output from the main shaft torque testing module. The control module calculates the impeller angle corresponding to the proximity switch triggering based on the number of proximity switch triggers and the forward / reverse rotation of the impeller. This wind turbine impeller detection method provides accurate calculation of the impeller angle, avoids the influence of impeller oscillation on the calculation results, and the structure is highly versatile, easy to install, and low in cost. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of the wind turbine rotor detection method provided in this embodiment of the invention. Figure 1 ;

[0031] Figure 2 This is a schematic diagram of the structure of the wind turbine rotor detection method provided in this embodiment of the invention. Figure 2 ;

[0032] Figure 3 This is a schematic diagram of the wind turbine rotor testing method provided in this embodiment of the invention. Figure 1 ;

[0033] Figure 4 This is a schematic diagram of the wind turbine rotor testing method provided in this embodiment of the invention. Figure 2 ;

[0034] Figure 5 This is a flowchart of the data acquisition module of the present invention performing arithmetic accumulation on the number of detection signals.

[0035] In the picture:

[0036] 1. Spindle locking disc; 2. Trigger structure; 3. Proximity switch; 4. Spindle torque testing module; 5. Control module; 51. Data acquisition unit; 52. Industrial computer. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0038] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used solely for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In the description of the present invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, the terms "first" and "second" are merely used for descriptive distinction and have no special meaning.

[0041] like Figures 1 to 5As shown, this embodiment provides a method for testing the impeller of a wind turbine, which can be applied to online load testing projects of gearboxes, effectively verifying product quality and playing a positive role in the verification and development of new products. Specifically, the impeller detection method for this wind turbine includes a main shaft locking disc 1, a proximity switch 3, a main shaft torque testing module 4, and a control module 5. The main shaft locking disc 1 is mounted on the main shaft of the wind turbine and rotates with the main shaft. Multiple trigger structures 2 are spaced circumferentially on the main shaft locking disc 1. The proximity switch 3 is fixed to the base, preferably by magnetic attraction, and is used to detect the trigger structures 2 and emit a detection signal. The main shaft torque testing module 4 is mounted on the main shaft and is used to output voltage signals based on the forward and reverse rotation of the main shaft. When the main shaft rotates forward, the main shaft torque testing module 4 outputs a positive voltage signal; when the main shaft rotates in reverse, the main shaft torque testing module 4 outputs a negative voltage signal. Both the proximity switch 3 and the main shaft torque testing module 4 are connected to the control module 5. The control module 5 receives the detection signals, performs an arithmetic accumulation of the number of detection signals, and calculates the impeller angle corresponding to the triggering of the proximity switch 3 based on the arithmetic accumulation value of the detection signals and the voltage signal. The specific method includes the following steps:

[0042] S1: After power-on, the impeller and main shaft rotate. When proximity switch 3 is initially triggered by a trigger structure 2, proximity switch 3 outputs the first detection signal, and control module 5 begins arithmetic accumulation of the number of detection signals. In this embodiment, a certain trigger structure 2 is marked as the initial trigger point. Before power-on or before proximity switch 3 begins triggering, the trigger structure 2 of the initial trigger point is adjusted to align with proximity switch 3, so that the initial rotation direction of the impeller is in a preset position when detecting the impeller angle, thereby improving detection accuracy. Specifically, as shown... Figure 2 As shown, the control module 5 includes a data acquisition unit 51 and an industrial control computer 52. The proximity switch 3 is connected to the data acquisition unit 51 by signal, and the data acquisition unit 51 is connected to the industrial control computer 52 by signal. When the trigger structure 2 triggers the proximity switch 3, the proximity switch 3 outputs a pulse signal, and the data acquisition unit 51 receives the pulse signal. The industrial control computer 52 is equipped with customized software to perform arithmetic accumulation on the detection signal, etc.

[0043] S2: Control module 5 calculates the impeller angle corresponding to the triggering moment of proximity switch 3 by using the arithmetic sum of the detection signals and the voltage signal output by spindle torque testing module 4. In this embodiment, when the impeller rotates forward, spindle torque testing module 4 outputs a positive voltage signal; when the impeller rotates in reverse, spindle torque testing module 4 outputs a negative voltage signal. By using the voltage signal output by spindle torque testing module 4 to determine whether the impeller is rotating forward or in reverse, and combining this information with the forward / reverse rotation of the impeller to calculate the impeller angle, the influence of impeller oscillation on the calculation results can be effectively avoided, thus improving the calculation accuracy.

[0044] When the impeller rotates, the main shaft locking disc 1 on the main shaft rotates accordingly, causing the triggering structure 2 to rotate relative to the proximity switch 3. Each time a triggering structure 2 passes the proximity switch 3, the proximity switch 3 is triggered to output a detection signal. The control module 5 arithmetically accumulates the number of detection signals. When the impeller rotates forward, the main shaft torque testing module 4 outputs a positive voltage signal; when the impeller rotates in reverse, the main shaft torque testing module 4 outputs a negative voltage signal. Thus, the control module 5 can determine whether the impeller is rotating forward or in reverse. The control module 5 calculates the impeller angle corresponding to the triggering of the proximity switch 3 based on the number of times the proximity switch 3 is triggered and the forward / reverse rotation of the impeller. This impeller detection method for wind turbines provides relatively accurate calculation of the impeller angle, avoids inaccurate calculation results caused by repeated accumulation of detection signals, and the structure has strong versatility, is easy to install, and has low cost.

[0045] Preferably, the interval between any two adjacent trigger structures 2 is equal, that is, the angle corresponding to the arc length between any two adjacent trigger structures 2 is equal. This facilitates the control module 5 in calculating the impeller angle corresponding to the triggering of the proximity switch 3 based on the arithmetic cumulative value of the detection signal and the angle corresponding to the arc length between any two adjacent trigger structures 2. For example, the angle corresponding to the arc length between any two adjacent trigger structures 2 is θ, and the number of trigger structures 2 is n. After the arithmetic cumulative value of the detection signal is zeroed, when a trigger structure 2 triggers the proximity switch 3 again, if the arithmetic cumulative value of the detection signal is 1, then the impeller angle corresponding to the trigger structure 2 triggering the proximity switch 3 is θ. When two trigger structures 2 trigger the proximity switch 3 in sequence, if the arithmetic cumulative value of the detection signal is 2, then the impeller angle corresponding to the second trigger structure 2 triggering the proximity switch 3 is 2θ, and so on. Furthermore, the control module 5 can determine whether the spindle is rotating forward or backward based on the output voltage signal of the spindle torque testing module 4, thereby correcting the arithmetic cumulative value of the detection signal and ensuring the accuracy of the calculation results.

[0046] Optionally, the trigger structure 2 is a bolt, with n bolts spaced evenly and circumferentially along the main shaft locking disc 1. Each time a bolt is aligned with the proximity switch 3, the proximity switch 3 is triggered to emit a detection signal. Of course, in other embodiments, the trigger structure 2 can also be other materials, such as a protruding pin, depending on the actual requirements.

[0047] Specifically, such as Figure 5As shown, when the impeller rotates forward, the main shaft torque testing module 4 outputs a positive voltage signal. The control module 5 receives the positive voltage signal. If the control module 5 receives the detection signal and performs arithmetic accumulation on the detection signal, it increments the accumulated value by one. That is, if the previous accumulated value of the detection signal is 'a', the accumulated value after incrementing by one is 'a+1'. When the impeller rotates in reverse, the main shaft torque testing module 4 outputs a negative voltage signal. The control module 5 receives the negative voltage signal. If the control module 5 receives the detection signal and performs arithmetic accumulation on the detection signal, it decrements the accumulated value by one. That is, if the previous accumulated value of the detection signal is 'a', the accumulated value after decrementing by one is 'a-1'. Then, the control module 5 can calculate the impeller angle corresponding to the triggering of the proximity switch 3 based on the accumulated value of the detection signal and the voltage signal. This avoids the situation where the accumulated value of the detection signal is still incremented by one when the impeller rotates in reverse, leading to inaccurate calculation results.

[0048] More specifically, the arithmetic accumulation of the detection signal includes the following steps:

[0049] When the arithmetic sum of the detection signal by control module 5 reaches n, control module 5 resets the arithmetic sum of the detection signal to zero and re-accumulates the number of detections. That is, when the arithmetic sum of the detection signal by control module 5 reaches n, it means that the impeller has completed one revolution. Control module 5 then re-accumulates the number of detections to avoid the arithmetic sum from continuously accumulating and increasing the computational load.

[0050] When the arithmetic sum of the detection signal is -1, it means that the impeller is reversing from the initial zero position. At this time, the arithmetic sum of the detection signal is corrected to n-1, and the arithmetic sum is recalculated on this basis. Forward rotation adds one, and reverse rotation subtracts one, to ensure that the impeller reversal control module 5 can also successfully calculate the impeller angle.

[0051] In this embodiment, when the impeller rotates forward, the main shaft torque testing module 4 outputs a positive voltage signal, with the first detection of the bolt by the proximity switch 3 as the zero position. As the impeller rotates, the bolts sequentially trigger the proximity switches 3. When the arithmetic sum of the detection signals is 'a', the impeller angle α corresponding to the most recent triggering of the proximity switch 3 is 'aθ'. When the impeller rotates in reverse, the main shaft torque testing module 4 outputs a negative voltage signal, and the impeller angle α corresponding to the most recent triggering of the proximity switch 3 is 'aθ+θ'. For example, when the impeller rotates forward and passes three bolts at proximity switch 3 (meaning the bolts have triggered proximity switch 3 three times), the arithmetic cumulative value of the detection signal is 3. Therefore, the impeller angle α corresponding to the third trigger of proximity switch 3 is 3θ, meaning the impeller angle at the moment the third bolt from the zero-position bolt passes proximity switch 3 is 3θ. If the impeller rotates in reverse, and proximity switch 3 is triggered again, the arithmetic cumulative value of the detection signal is 2. The impeller angle α corresponding to the fourth trigger of proximity switch 3 is still 3θ, meaning the impeller angle at the moment the third bolt from the zero-position bolt passes proximity switch 3 is still 3θ. The calculation result is accurate, avoiding the influence of impeller rotation on the calculated impeller angle. Furthermore, when the impeller rotates in reverse past the zero-position bolt and triggers proximity switch 3 again, the arithmetic cumulative value of the detection signal is corrected to n-1, and the arithmetic cumulative value is recalculated based on this, using the same method as above, which will not be elaborated further here.

[0052] Furthermore, such as Figure 4 As shown, after the control module 5 calculates the impeller angle corresponding to the triggering moment of the proximity switch 3, the following steps are also included:

[0053] S3: Control module 5 calculates the average impeller angular velocity based on the difference in impeller angles corresponding to two consecutive triggering of proximity switch 3 and the corresponding time interval. For example, if the time interval between two consecutive triggering of proximity switch 3 is Δt, and the difference in impeller angles corresponding to two consecutive triggering of proximity switch 3 is Δα, then the average impeller angular velocity ω = Δα / Δt.

[0054] After calculating the average impeller angular velocity ω, the following steps are also included:

[0055] S4: Control module 5 calculates the impeller angle at any given time based on the average impeller angular velocity ω and the impeller angle α corresponding to the triggering of proximity switch 3. That is, by calculation, the impeller angular velocity for each time period can be obtained, and the impeller angle at each triggering of proximity switch 3 can also be obtained, i.e., the impeller angle at each recorded time point. Therefore, the impeller angle at any given time can be obtained based on ω and α.

[0056] After calculating the average impeller angular velocity ω, the control module 5 can also calculate the impeller rotation speed based on the average impeller angular velocity ω. That is, if the circumference of the circle where the multiple trigger structures 2 are located is r, then the impeller rotation speed is v = ωr.

[0057] Furthermore, the impeller detection method for this wind turbine also includes a moment patch, which is installed on the main shaft to measure the absolute bending moment value of the main shaft. The moment patch is connected to the control module 5 via a signal. After the control module 5 calculates the impeller angle at any given time, the method further includes the following steps:

[0058] S5: Real-time detection of the absolute bending moment value of the spindle via a bending moment patch;

[0059] S6: Control module 5 calculates the equivalent bending moment values ​​of the fan in the horizontal and vertical directions based on the absolute bending moment value and the impeller angle at the corresponding moment.

[0060] When measuring the actual bending moment borne by the main shaft online using a moment patch attached to the main shaft, the collected bending moment data is the absolute bending moment at the test point on the main shaft because the moment patch rotates with the main shaft. In this embodiment, after measuring the absolute bending moment value at a certain moment, the impeller angle at that moment is calculated based on the average impeller angular velocity ω and the impeller angle α corresponding to the triggering of proximity switch 3. Then, the equivalent bending moment values ​​of the wind turbine in the horizontal and vertical directions are calculated. In the prior art, the scheme of measuring the impeller angle using an inductive encoder has many problems, such as the need to customize the encoder according to the size of the transmission chain, whether there is corresponding installation space and position on the transmission chain, and the need to prepare and submit the encoder fixing and subsequent disassembly plan for customer review. For equipment testing manufacturers, this results in many disadvantages, such as increased testing costs, significantly extended test preparation cycle, and poor universality of customized encoders. The wind turbine impeller detection method provided in this embodiment can solve the above problems and has the advantages of low cost and accurate calculation results.

[0061] The wind turbine rotor testing method provided in this embodiment does not involve disassembling or reassembling existing equipment or components inside the turbine, and has zero risk to the normal operation of the equipment. Compared with the traditional method of making a custom induction encoder and fixing it to the drive chain, the equipment is easy and quick to install, the turbine downtime is greatly shortened, and the power generation loss during downtime is reduced. It has an independent data acquisition system, which is safe and reliable. It has strong versatility and can be tested on doubly-fed wind turbines and semi-direct drive / direct drive wind turbines with rotor locking discs designed inside the nacelle. At the same time, based on the turbine rotor angle test, the main shaft speed and equivalent bending moment can be measured.

[0062] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method of detecting a blade of a wind power generator, characterized in that, The wind turbine includes: The main shaft of the wind turbine is sleeved with a main shaft locking disc (1), which can rotate with the main shaft, and a plurality of trigger structures (2) are arranged on the main shaft locking disc (1) in a circumferential direction; A proximity switch (3) is fixedly arranged on the base, and a main shaft torque test module (4) is arranged on the main shaft, which is used to output a voltage signal according to the forward rotation and reverse rotation of the main shaft, and the proximity switch (3) and the main shaft torque test module (4) are signal connected with a control module (5); After starting, the impeller and the main shaft rotate, when the proximity switch (3) is triggered by a trigger structure (2) for the first time, the proximity switch (3) outputs a first detection signal, and the control module (5) starts to arithmetically accumulate the number of detection signals; The control module (5) calculates the impeller angle corresponding to the triggering time of the proximity switch (3) by the arithmetically accumulated value of the detection signal and the voltage signal output by the main shaft torque test module (4); After the control module (5) calculates the impeller angle corresponding to the triggering time of the proximity switch (3), the following steps are further included: the control module (5) calculates the average impeller angular velocity according to the difference between the impeller angles corresponding to the triggering times of the proximity switch (3) and the corresponding time interval; After the control module (5) calculates the average impeller angular velocity, the following steps are further included: the control module (5) calculates the impeller angle at any time according to the average impeller angular velocity and the impeller angle corresponding to the triggering time of the proximity switch (3); A bending moment patch is further included, which is arranged on the main shaft and is used to measure the absolute bending moment value of the main shaft, the bending moment patch is signal connected with the control module (5), and after the control module (5) calculates the impeller angle at any time, the following steps are further included: the control module (5) calculates the equivalent bending moment value of the wind turbine in the horizontal and vertical directions according to the absolute bending moment value and the impeller angle at the corresponding time; When the impeller rotates forward, the voltage signal output by the main shaft torque test module (4) is a positive voltage signal, when the impeller reverses, the voltage signal output by the main shaft torque test module (4) is a negative voltage signal, and when the control module (5) arithmetically accumulates the detection signal, it adds one according to the positive voltage signal or subtracts one according to the negative voltage signal.

2. The wind power generator blade inspection method according to claim 1, wherein The number of the trigger structures (2) is n, and when the control module (5) arithmetically accumulates the detection signal, the following steps are included: When the arithmetically accumulated value of the detection signal by the control module (5) is n, the control module (5) clears the arithmetically accumulated value of the detection signal and re-arithmetically accumulates the number of detection signals; When the arithmetically accumulated value of the detection signal by the control module (5) is -1, the control module (5) corrects the arithmetically accumulated value of the detection signal to n-1, and re-arithmetically accumulates on this basis.

3. The wind turbine blade inspection method of claim 2, wherein, Intervals between every two adjacent trigger structures (2) are equal, and an included angle corresponding to an arc length between every two adjacent trigger structures (2) is θ; When the control module (5) receives the positive voltage signal and an arithmetic cumulative value of the detection signal is a, the impeller angle α corresponding to a triggering time of the proximity switch (3) is aθ; When the control module (5) receives the negative voltage signal and an arithmetic cumulative value of the detection signal is a, the impeller angle α corresponding to a triggering time of the proximity switch (3) is aθ+θ.

4. The wind power generator blade inspection method according to claim 1, wherein After the control module (5) calculates the average impeller angular velocity, the control module (5) can calculate the rotating speed of the impeller according to the average impeller angular velocity.

5. The wind turbine blade inspection method according to any one of claims 1 to 3, wherein The control module (5) comprises a data collector (51) and an industrial computer (52), the proximity switch (3) is signal-connected with the data collector (51), the data collector (51) is signal-connected with the industrial computer (52), when the trigger structure (2) triggers the proximity switch (3), the proximity switch (3) outputs a pulse signal, the data collector (51) receives the pulse signal, and the industrial computer (52) performs arithmetic cumulative operation on a number of the pulse signals received by the data collector (51).

6. The wind turbine blade inspection method according to any one of claims 1 to 3, wherein The trigger structure (2) is a bolt, a plurality of the bolts are arranged on the main shaft locking disc (1) along a first circumference, the proximity switch (3) is opposite to a position where the first circumference is located, and when one of the bolts is opposite to the proximity switch (3), the proximity switch (3) outputs one detection signal.

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